Are Miami's opponents picking on Jimmy Wilson?

DAVIE - A month ago Jimmy Wilson was just a fill-in holding down the fort for an injured Richard Marshall.

The converted safety was filling in as the Miami Dolphins' nickel cornerback, playing what happens to be one of the most challenging positions in football.

But with Marshall going on injured reserve last week because of the back injury he's been nursing for a month it appears Wilson, a seventh-round pick in 2011, will have to man the nickel spot for the rest of the season.

If that's the case he'll also have to step his game up because the Colts and Titans have targeted the former Montana standout the past few games. And Buffalo, who regularly uses a spread offense, leans heavily on the spot receiver.

ProFootballFocus.com rates Wilson has the 86th best cornerback in the NFL, and his rating is in a steady decline.

Opposing quarterback have a 107.3 quarterback rating when throwing to a receiver Wilson is defending. That's the highest rating of every player in Miami's secondary.

“He has to be more consistent in his coverage. He's had a couple third down conversions against him, both last week and against [Tennessee],” defensive coordinator Kevin Coyle said. “That was a big issue [against the Titans] for us defensively. We’ve been playing good on third down but the last two weeks we’ve been poor.”

The Dolphins don't have many options outside of Wilson, who has worked as the backup nickel since training camp.

Sean Smith (rated by PFF as No. 22) and Nolan Carroll (No. 60) serve as the starting boundary corners. One of them could man the nickel spot, allowing another cornerback to handle the boundary. The only other options are R.J. Stanford, a waiver wire claim who has been with the Dolphins since week one, and Bryan McCann, who was signed last week.

Wilson, who has contributed 22 tackles, two sack and one forced fumble, is a very physical player, which explains his move from cornerback to safety this offseason. But to man the nickel spot, where he'll face some of the most athletic and shifty receivers in the NFL (think Wes Welker), he'll need to improve his coverage skills.